The present invention relates to sliding vane machines comprising in combination a housing, a rotor being rotatable therein, a plurality of axial grooves spaced evenly along the circumference of said rotor, each one of said grooves supporting two vanes, which vanes are axially displaceable in said groove between a first position in which they are entirely contained inside said groove, to a second position in which each separate vane projects axially from the rotor, a number of radially extending partition walls fixed in the housing and dividing the interior thereof into a plurality of pressure chambers, guide means in the housing adapted to bring said vanes to their said first position when a groove during the rotational movement of the rotor passes one and each of said partition walls, a fluid inlet in each one of said pressure chambers, a fluid supply line common for all fluid inlets, a fluid outlet in each one of said pressure chambers, a fluid discharge conduit common for all fluid outlets.
Machines of this kind can be used as a motor, whereby the pressure chambers are fed with a pressure fluid, the work of the motor thereby being taken out via the rotor shaft. It is also possible to use the machine as a pump, whereby the rotor shaft is rotated and the rotor is thereby brought to displace the fluid.
In both cases is it desirable that the working characteristics of the machine can be altered during operation in order to be adapted to varying external loads or according to varying performance demands respectively.